Risk group stratification and prognostic factors in papillary carcinoma of thyroid.

BACKGROUND

Our understanding of the natural history of differentiated thyroid carcinoma has improved with the definition of prognostic factors. These prognostic factors have helped us identify patients in various risk groups.

METHODS

A retrospective review of a consecutive series of 810 previously untreated patients with papillary carcinoma of the thyroid was undertaken to analyze the prognostic factors and risk groups. There were 403 patients in the low-risk group, 313 in the intermediate group, and 94 classified in the high-risk group.

RESULTS

With a median follow-up of 20 years, 99% survival was achieved in the low-risk group, whereas only 43% survived in the high-risk group. The intermediate-risk group had a 20-year survival of 83%. The favorable prognostic factors included female sex, young age, absence of distant metastases and extrathyroidal extension of the disease, size < 4 cm, and low-grade histology. Focality, presence of lymph node metastasis, and pure papillary or mixed variant had no statistical significance on prognosis.

CONCLUSIONS

Based on various prognostic factors, low-, intermediate-, and high-risk groups are identified. Patients in the low-risk group have excellent survival (99%). Appropriate selection of surgical and adjuvant treatment should therefore be used based on prognostic factors and risk group stratification.